Numerical modelling of UV intensity: Application to collimated-beam reactors and continuous-flow systems

When properly designed, collimators can be used to develop a source of electromagnetic radiation which is uniform and easily quantified. A collimator design is presented which minimizes reflection and promotes the development of a well-behaved, quantifiable radiation source. The design of the collimator is optimized by use of a numerical model, line source integration (LSI), a continuous version of the widely used point-source summation technique. The LSI model is used to quantify the radiation intensity field from a collimator which incorporated a standard low-pressure mercury arc lamp as its source of radiation. A method of measuring lamp output power is also demonstrated which employs experimental measurements of intensity through a collimator and the LSI model. The physical meaning of this measurement, its limitations and potential applications are discussed.